Microwave Journal
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An Eight-channel YIG-tuned Frequency Synthesizer Array

Development of a new YIG-based frequency synthesizer array that provides up to eight independent frequency channels

May 1, 2002

Product Feature

An Eight-channel YIG-tuned Frequency Synthesizer Array


Micro Lambda Wireless Inc.
Fremont, CA

Low phase noise is a staple of modern communication systems signal sources. For that reason system designers prefer yttrium iron garnet (YIG)-based sources. In addition, many of today's communications systems are required to operate at multiple frequency bands, while still maintaining low phase noise performance. To address these needs, a new YIG-based frequency synthesizer array has been introduced that provides up to eight independent frequency channels in a single 19" rack enclosure.

The MLSA-series frequency synthesizer arrays are designed to be the main local oscillators in simulation systems, communications systems and test sets. They are comprised of up to eight independent YIG-based phase-locked loop (PLL) synthesized channels that are 2 to 3 GHz wide up to 12 GHz. Each channel has a standard resolution of 500 kHz, both in the narrow band and wide band models. Optional frequency resolution to 125 kHz can be provided by simple programming via a RS232 standard interface with a 19,200-baud rate.


Fig.1 Single-sideband phase noise performances.

The synthesizer array delivers between +8 and +12 dBm output power depending on the frequency band of operation with maximum output power variations of ±2 dB due to temperature and frequency. Optional dual RF output ports for each independent frequency channel are available thus providing 16 RF outputs in a single 19" rack enclosure.

The harmonic levels of this multi-octave source are moderately controlled at -12 to -15 dBc. However, the spurious levels are held to better than -60 dBc for all frequency offsets. In addition, the phase locked phase noise is excellent. As shown in Figure 1 , single-sideband (SSB) phase noise for a single channel from 8 to 10 GHz is -93 dBc/Hz for a 10 kHz offset from the carrier, -117 dBc/Hz for a 100 kHz offset and -140 dBc/Hz for a 1 MHz offset; it continues downward to a noise floor below -155 dBc/Hz. The MLSA-1100 series synthesizer arrays can also be provided with an optional internal, high performance 10 MHz crystal reference oscillator and/or an optional microwave switch for turning frequency bands into a single output.


Fig. 2 The array synthesizer's rear panel.

Powered by 120/240 V AC, the synthesizer array draws 300 mA at +120 V AC for a dual band array and 1200 mA for an eight-band array. The unit is supplied in a standard rack enclosure measuring 19" x 15" x 3.5" high with female SMA connectors for the RF outputs. An SMA connector is provided for the external reference supplied by the user and a nine-pin connector is included for the RS232 communication lines, as shown in Figure 2 . A fault/lock indicator circuit is also supplied. The synthesizers are designed to operate into a maximum SWR of 1.50 and handle operating temperatures from -0° to +55° C. Table 1 lists the available 2 GHz tuning range models in the series. Additional information may be obtained via e-mail at sales@microlambdawireless.com. The new synthesizers are available for delivery eight weeks after receipt of order.

Table 1
MLSA-Series of 2 GHz Tuning Range Synthesizers

Model

Frequency Range (GHz)

Channel

MLSA-1108-001

2.0 to 4.0
4.0 to 6.0
5.0 to 7.0
6.0 to 8.0
7.0 to 9.0
8.0 to 10.0
9.0 to 11.0
10.0 to 12.0

1
2
3
4
5
6
7
8

MLSA-1104-001

2.0 to 4.0
4.0 to 6.0
5.0 to 7.0
6.0 to 8.0

1
2
3
4

MLSA-1102-001

2.0 to 4.0
4.0 to 6.0

1
2

Micro Lambda Wireless Inc., Fremont, CA (510) 770-9221, www.microlambdawireless.com.
Circle No. 304